1. Field of the Invention
The present invention relates to locomotive braking systems and, more particular, to an automatic bail off during brake applications.
2. Description of the Related Art
A locomotive operator using a pneumatic or electro-pneumatic braking system is required to make a reduction in the brake pipe (BP) pressure to apply the train brakes. Due to operating rules or conditions of train control, the locomotive operator may have to perform a bail off that prevents the locomotive brake cylinders from applying while a reduction in brake pipe pressure is made to apply the train brakes. Generally, the term bail off is used to refer to the removal of pressure from the brake cylinders of a locomotive or multiple locomotives in a consist.
To accomplish the application of the train brakes and a bail off of the locomotive brakes, the locomotive operator must perform two operations simultaneously, which typically requires the use of both hands on the equipment that allows the operator to apply the train brakes while preventing the locomotive brake cylinders from applying. A locomotive operator has, however, many other demands on his or her attention in situations where the train brake are being applied. The act of bailing off the locomotive brakes must happen regardless of the situation and therefore is an added activity that can distract from other decisions and actions that the locomotive operator must perform, such as determining the appropriate amount of brake pipe reduction to be made, deciding whether dynamic braking should be applied, etc. Similar decisions and operations must also be made in electronically controlled pneumatic (ECP) brake control systems with respect to the train brake command (TBC) communication level and the resulting effect on the locomotive brake cylinder pressure. Accordingly, there is a need in art for a system that can reduce the level of input needed from the locomotive operator to bail off the locomotive brakes during a train braking event.